Chemical conversions employing solid catalysts are often conducted using a fixed or fluidized bed of catalyst particles. That is, the material to be converted is contacted with a solid catalyst present in a fixed bed of particles or in a fluidized bed of particles. however, each of these two modes of operation has serious disadvantages. For example, the use of a fixed catalyst bed often results in temperature control problems which adversely affect catalyst performance. Regeneration and/or reactivation of a fixed catalyst bed can result in substantial process downtime since the chemical conversion must be stopped in order to treat the catalyst, e.g., while the catalyst remains in the reactor vessel. Obtaining a uniform catalyst activity distribution is also difficult with fixed catalyst beds, in particular in situations where frequent regenerations are required.
Fluidized catalyst beds do, in general, provide better temperature control than do fixed catalyst beds. However, fluidized catalyst bed reaction systems are also much more complex than fixed catalyst bed reaction systems. For example, fluidized catalyst bed reaction systems usually involve at least two separate vessels each containing a fluidized catalyst bed, one in which to conduct the chemical conversion and one in which to regenerate and/or reactivate the catalyst. Catalyst particles are transferred, e.g., substantially continuously transferred, between the two separate vessels. Separation devices, e.g., cyclone separators and slide valve assemblies, are often needed to separate the catalyst particles from the feedstock/reaction product and the regeneration/reactivation medium and to control the flow of catalyst between the two vessels. Also, the catalyst particles, although relatively small to permit fluidization, must be blended to include added components, such as binders and often fillers, to strengthen the particles, e.g., against attrition, so that the particles can better withstand the constant and sometimes rather turbulent motion in the fluidized catalyst bed reaction system and separation devices. These added components, which are also often present in fixed bed catalysts as well, often promote undesirable chemical reactions or otherwise detrimentally affect the catalytic performance of the catalyst. Also, these added components may be particularly troublesome when used in conjunction with crystalline microporous three dimensional solid catalysts or CMSCs, i.e., catalysts which promote chemical reactions of molecules having selected sizes, shapes or transition states.
One alternative chemical reaction system involves the use of a catalyst slurry. In "Heterogeneous Catalyst in Practice" by Charles N. Satterfield, McGraw-Hill Book Company, New York (1980), at page 317 it is stated:
"The reaction of a liquid is often carried out by suspending a solid catalyst in a finely divided form in the liquid. This is often termed a slurry reactor'. If a gas is to be reacted with a liquid, it may be introduced through a distributor in the bottom of the vessel or it may be dispersed into the liquid by a mechanical agitator. This also acts to keep the solid suspended." PA1 w is equal to 0 to 99 mole percent; PA1 y is equal to 1 to 99 mole percent; PA1 x is equal to 1 to 99 mole percent; and PA1 z is equal to 0 to 99 mole percent. FNT .sup.1 See the discussion at pages 8a, 8b and 8c of EPC Publication 0 159 624, published Oct. 30, 1985, about the characterization of "EL" and "M". Such are equivalent to Q as used herein.
Thus, "slurry reactor" in the prior art is used to carry out a reaction of a liquid or of a gas and a liquid in the presence of a catalyst. For example, the Phillips Petroleum Company process for producing high density polypropylene utilizes slurry reactors. A fair amount of research effort has been directed to the use of slurry reactors, e.g., for making methanol from synthesis gas and for application to the Fisher-Tropsch reaction. See, for example, M. B. Sherwin, et al, "Make Methanol by Three Phase Reaction", Hydrocarbon Processing, p. 122-124, November, 1976; U.S. Pat. Nos. 3,888,896 and 4,031,123; M. L. Riekena, et al, "A Comparison of Fisher-Tropsch Reactors", Chemical Engineering Progress, p. 86-90, April, 1982; C. N. Satterfield, et al, "Usefulness of a Slurry Type Fishcher-Tropsch Reactor for Processing Synthesis Gas of Low Hydrogen-Carbon Monoxide Reactors", Canadian Journal of Chemical Engineering, Vol. 60, p. 159-162, 1982.
Slurry reaction system do provide substantial benefits. For example, temperature control is relatively easily maintained in such systems. However, selectivity to desired products may suffer because of relatively prolonged contacting between the catalyst and liquid reactant and product. It would be advantageous to provide a new chemical conversion process employing a solid catalyst.
Methanol is readily producible from coal and other raw materials by the use of well-known commercial processes. For example, synthesis gas can be obtained by the combustion of any carbonaceous material including coal or any organic material such as hydrocarbons, carbohydrates and the like. The synthesis gas can be manufactured into methanol by a well known heterogeneous catalytic reaction.
"Hydrocarbons from Methanol" by Clarence D. Chang, published by Marcel Dekker, Inc. N.Y. (1983) presents a survey and summary of the technology described by its title. Chang discusses methanol to olefin conversion in the presence of molecular sieves at pages 21-26. The examples given by Chang as suitable molecular sieves for converting methanol to olefins are chabazite, erionite, and synthetic zeolite ZK-5.
Catalysts comprising one or more crystalline microporous three dimensional materials or CMSMs include naturally occurring molecular sieves and synthetic molecular sieves, together referred to as "molecular sieves," and layered clays.
Among the CMSMs that can be used to promote converting methanol to olefins are non-zeolitic molecular sieves or NZMSs, such as aluminophosphates or ALPOs, in particular silicoaluminophosphates or SAPOs disclosed in U.S. Pat. No. 4,440,871. U.S. Pat. No. 4,499,327, issued Feb. 12, 1985, discloses processes for catalytically converting methanol to light olefins using SAPOs at effective process conditions. Each of these U.S. Patents is incorporated in its entirety by reference herein. Also, see commonly assigned U.S. Patent Applications, Ser. Nos. 070,574, 070,575 and 070,578, all filed on an even date herewith. Each of these applications is incorporated in its entirety by reference herein.